To compare the efficacy and tolerability of intravenous artesunate for the initial treatment of uncomplicated Plasmodium falciparum malaria at doses that bracket anticipated clinical doses (2.4 mg/kg once daily for 3 days; or 2.4 mg/kg initially, at 12 hours on Day 0, and then daily on Day 1 and 2) and thereby establish the safest, highly efficacious dosing regimen for use in future clinical trials.